Anticorrosion agent



United States Patent ANTICORROSION AGENT George N. Butter, Terre Hante,Ind., assignor to Commercial Solvents Corporation, Terre Haute, Ind., acorporation of Maryland No Drawing. Application July 24, 1956 Serial No.599,681

4 Elaims. (Cl. 252-392) My invention relates to corrosion inhibitingcompositions and more particularly it is concerned with an anticorrosioncomposition containing as an essential active ingredient a substitutedoxazoline having the formula where R is one of the group consisting ofC1'7H35 and C1'7H33, and to a process for preventing corrosiontherewith.

Many difierent agents have been discovered which are efiective corrosioninhibitors under limited conditions. However, since no acceptable theoryhas been advanced to delineate the mode of operation of corrosioninhibitors, extensive experimentation is required to develop inhibitorshaving special properties which can be utilized for a particularpurpose.

I have now discovered that certain oxazolines impart to ferrous metalsresistance to attack by a variety of corrosion agents in both acidic andbasic solutions.

The word ferrous used in this application is to be interpreted as ironcontaining and does not mean iron in the bivalent state.

My new compositions utilize as the essential active ingredient 2(8-heptadecenyl) 4,4 bis(hydroxymethyl)-2-oxazoline or2-heptadecyl-4,4-bis(hydroxymethyl)- 2-oxazoline dissolved in an oilbase. The oxazolines employed in my invention are conveniently producedby reacting tris(hydroxymethyl)amino methane with oleic or stearic acidin approximately equimolar quantities. The temperature employed incarrying out the reaction is preferably maintained between 160 and 185C. The initial stage of this reaction yields an amide corresponding tothe desired product, after which the temperature is increased toapproximately 215 C., or higher, thereby resulting in the thermalelimination of one equivalent of Water to give the desired oxazoline.Generally, the oxazolines can be produced according to the processdescribed in US. Patent 2,402,791.

I have found that I can employ either crude or refined mineral orvegetable oils as the inert base of my corrosion inhibiting composition.In preparing my new composition, I can incorporate from 0.04 to 10% byweight of the active ingredient in the inert oil base by any convenientmeans. I prefer to employ about 1% by weight of the oxazoline in my newcomposition.

To illustrate the effectiveness of my invention, the following examplesare set out; however, I do not intend to be limited to the particularmaterials, procedures or amounts set forth but rather I intend for allequivalents obvious to those skilled in the art to be included withinthe scope of my specification and claims.

EXAMPLE 1 A series of static water drop tests were conducted employing aprocedure described by Baker, Jones, and Zisman in Industrial andEngineering Chemistry, vol. 41, pages 137-144 (1949). Generally, thetest consisted of submerging a test specimen; prepared by depressing thecenter portion of a triangular piece of inch S.A.E. 1020 cold rolledsteel, polishing the depression to a mirror finish, andbending thecorners of the triangle down to form legs; in a beaker containing thecomposition of my invention and injecting 0.2 ml. of water into thedepres sion. The containers were covered and placed in a constanttemperature oven at 160 F. and visually'inspected at intervals.

The following table sets out the results of the abovedescribed testsshowing the condition of the test specimens while submerged incompositions of my invention containing varying amounts of the activeagents at the end of various time periods up to 351 hours when the ATestarea of disk bright.

B-Test area bright except for 1 small rust spot. This failure may resultfrom an imperfect disk.

C-Test area of disk completely rusted.

EXAMPLE II The results of a test utilizing a procedure described inCorrosion, vol. 11, No. 3, pages 143t-146t (1955), demonstrate theefficacy of my new composition in the presence of hydrosulfuric acid.The test described is a static oil and water test wherein mild steelcoupons are contacted with a brine containing hydrosulfuric acid. Theweight loss of a coupon coated with my new composition is compared withthe weight loss of a coupon coated with the inert oil base of my newcomposition.

The per cent protection effected by use of my compositions is set outbelow.

Table II Concentration Percent of inhibprotec- Compound itor in tion inmineral test oil, p.p.m.

2- (8-heptadecenyl) -4,4-bis (hydroxymethyD-Z-oxaz ine 96.6 2-heptadecyl-4,4-bis (hydroxymethyl)-2-0xazoline. 100 97. 2

Now having described my invention, what I claim is: 1. A corrosioninhibiting composition comprising a mineral oil solvent in a majoramount, based on the weight of the composition, and from about 0.04% to10% of a substituted oxazoline having the structural formula where R isa radical selected from the group consisting Of C17H35 and C17H33.

2. A corrosion inhibiting composition comprising a vegetable oil solventin a major amount based on the weight of the composition, and from about0.04% to 10% of a substituted oxazoline having the structural formulawhere R is a radical selected from the group consisting of 17 s5 nCHI-I332 v t t.

3. A process for the prevention of corrosion to ferrous metal surfaceswhich comprises applying to the ferrous metal surfaces a compositioncomprising a mineral oil containing from 0.04% to 10% of a substituted'oxazoline having the structural formula OH H (EH, H-l-G-CHaOH where Ris a radical selected from the group consisting of C17H35 and C17H33- 4.A process for the prevention of corrosion to ferrous A metal surfaceswhich comprises applying to the ferrous metal surfaces 21 Vegetable oilcontaining from 0.04% to 10% of a substituted oxazoline having thestructural formula where R is a radical selected from the groupconsisting Of C I I 5 and C17H3 References Cited in the. file of thispatent UNITED STATES PATENTS 2,402,791 Wampner June 25, 1946 2,566,793Davis et a1 Sept. 4, 1951 2,652,363 Woods et al Sept. 15, 1953 2,737,491Hughes et a1. Mar. 6, 1956

1. A CORROSION INHIBITING COMPOSITION COMPRISING A MINERAL OIL SOLVENTIN A MAJOR AMOUNT, BASED ON THE WEIGHT OF THE COMPOSITION AND FROM ABOUT0.04% TO 10% OF A SUBSTITUTED OXAZOLINE HAVING THE STRUCTURAL FORMULA